Vinyl chloride resins plasticized with copolymers of an acrylate and either ethylene or propylene



United States Patent VINYL CHLORIDE RESINS PLASTICIZED WITH COPOLYMERSOF AN ACRYLATE AND ElTHER ETHYLENE OR PROPYLENE Clifford E. Baimer,Holland, Clarence A. Brown, Hatboro, and Melvin D. Hurwitz, Southampton,Pa., and James E. Masterson, Moorestown, NJ, assignors to Rohm & HaasCompany, Philadelphia, Pa., a corporation of Delaware No Drawing. FiledNov. 14, 1962, Ser. No. 237,735

7 Claims. (Cl. 260.31.8)

This is a continuation-in-part of our application Serial No. 820,625,which was filed on June 16, 1959, and which was issued as US. Patent No.3,089,897, on May 14, 1963.

The parent application disclosed our unique process for copolymerizingethylene and an acrylate by which novel compounds are prepared. By thesame process propylene and an acrylate are copolymerized to form similarcompounds. The products of that process are especially useful asplasticizers for vinyl type compositions, particularly for thehomopolymers and copolymers of vinyl chloride. By the term acrylate,incidentally, as used generically in the parent application andthroughout the specification and claims hereof, is meant both the estersof acrylic and methacrylic acid, both substituted and unsubstituted,unless one or the other is more specifically named. The termhomopolymers and copolymers of vinyl chloride, moreover, refers topolymers of vinyl chloride selected from the group consisting ofhomopolymers of vinyl chloride and copolymers of a major portion of (orat least 50% of) vinyl chloride with an ethylenically unsaturatedmonomer copolymerizable therewith.

The plasticizer compounds, which are described in detail in the parentapplication, and which description is incorporated herein by reference,are fluid materials that are characterized by their exceptionally lowmolecular weight for the types of copolymers involved. They maygenerally be defined in the following terms:

(1) Molecular weight (ebulliometric); ranging between 500-1500.

(2) Viscosity ranges from H to Z on the Gardner- Holdt scale (equivalentto 2-985 poises) when ethylene is the olefin employed, and from H to Z(equivalent to 21066 poises) when propylene is copolymerized with theacrylate.

(3) Light color (characteristically 1, but in any event no more than 3,on the Gardner 1933 scale).

(4) Acid numbers generally below 1, but in any case no more than about3.0.

(5) Molar ratio of ethylene to acrylic monomer ranging from 1.0 to 3.0,and a molar ratio of propylene to acrylic monomer ranging from 0.5 to2.0, both depending on the acrylic monomer employed. The upper limit isa function of molecular weight, as expressed by the equations:

(A) moles of ethylene/mole of acrylic monomer X+/4 molecular Weight)where X=1.75 for ethyl acrylate and methyl methacrylate, and X=2.25 formethyl acrylate; and

"ice

(B) Moles of propylene/mole of acrylic monomer 1500 (molecular weightwhere X=1.00 for ethyl acrylate and methyl methacrylate, and X=1.25 formethyl acrylate.

The broad and preferred ranges of the molar ratios of ethylene andpropylene, respectively, to the acrylic monomer, and the molecularweight of the product obtained by any pair of the monomer and one ofsaid olefins, can conveniently be ascertained from Table l[ whichfollows:

TABLE I Ethyleneacrylate Molecular mole ratio in weight productr PART AMethyl acrylate:

Broad range 1. 0-3. 0 500-1. 500 Preferred range 1. 7-2. 2 700-900 Ethylacrylate:

Broad range 1. 0-2. 5 500-1, 500 Preferred range 1. 3-2. 0 700-900Methyl methacrylate:

Broad range 1. 0-2. 5 500-1, 500 Preferred range 2. 0-2. 5 500-800Propylene- PART B acrylate,

mole ratio in product.

Methyl acrylate:

Broad range 0. 5-2. 0 500-1, 500 Preferred range 1. 0-1. 5 500-800 Ethylacrylate:

Broad range 0. 5-1. 500-1, 500 Preferred range 0. 75-1. 25 500-800Methyl methacrylate:

Broad range 0. 5-1. 75 500-1, 500 Preferred range 0. 75-1. 25 500-800Characteristically, the higher the amount of ethylene or propylene whichis incorporated in the copolymer product, the lower must be themolecular weight for the material. Thus, in the copolymer formed fromethylene and methyl acrylate, an average molecular Weight of about 500is suitable for a composition in which the mole ratio of ethylene tomethyl acrylate is 3.0; but this mole ratio must be reduced to 2.25 asan average molecular weight of 1500 is approached. Similarly, in thecopolymer formed from propylene and methyl acrylate, an averagemolecular weight of about 500 is suitable for a composition in which themole ratio of propylene to methyl acrylate is 2.0; but this mole ratiomust be reduced to 1.50 as an average molecular weight of 1500 isapproached. Recognition of these critical elements of the invention ismade in the simple formula given above which relates the permissibleupper limit of the olefin content to the molecular weight.

When employed as a plasticizer for vinyl type compositions thesecompounds give maximum performance if the acidity of the copolymers iskept low, preferably an acid number of no more than 3.0. This makespossible the obtainment of high volume resistivity when the plasticizedproduct is used as an electrical insulator, for example.

The plasticizers are all liquid, and are generally light in color. TableII, which follows, summarizes the performance properties of a number ofthem, almost all being compounds whose preparations are individuallydescribed in examples set forth in the parent application, the remainderhaving been prepared by closely analogous methods. In each case 40 partsof the plasticizer was incorporated with 60 parts of polyvinyl chlorideand 1 part of a stabilizer (co-precipitated barium cadmium laurate), ona weight basis, in accordance with a conventional manner forplasticizing such materials.

The test methods listed in Table II for determining the variousproperties of the polyvinyl chloride materials which were plasticizedwith the copolymers of the parent application are well known. However,for anyone not familiar with those methods they can readily be found inthe publication entitled Plasticizers (Rohm & Haas Company,Philadelphia, Pennsylvania, 1954, at pages 66-70).

The performance properties identified in Table II give clear indicationof the utility of the plasticized compositions of the present invention.

TABLE 11 Performance properties of plasticized polymeric vinyl chloridecompositions Shore 90 C. Activated Plasticizer A Torsional soapy Hexanecarbon composition hardmodulus water extracvolatility,

N 0. ness, (Tissues) cxtrac- Lion, percent 10 see. 0. tion, percent losspercent DOP 69 35 9 30 10 DOP 66 31 8.8 30.9 7. 3

Notes:

(a) Dioctyl phthalate, a widely used commercial plasticizer, cited hereas a reference for comparison of its properties with the properties ofplasticizer compositions No. '19, 1-1 and 112 employing a polyvinylchloride homopolymer resin.

( b) Used as a plasticizer for a vinyl chloride/vinyl acetate copolymerresin identical with the one employed with plasticizer composition No.10.

(c) Following are the charges from which the plasticizer compositionswere made in accordance with the method described generally, and in theexamples specifically, in thc parent application S.N. 820,625 (in whichthe abbreviations refer to the following: Ezethylene; Pzpropylene; ethylacrylate; M-Azmethylacrylate; and M'MAzmethyl methacrylate,tAP.BA:tertiary Idutyl peracetate (75%), and d-t-BP di-t-butyl peroxide(97%) (1) 1300 g. EA, 4 g. E, and 63.4 g. t-PBA.

250 g. MMA, 525 g. E, 1 g. cumene, 74.8 t-PBA '3) 300 g. EA, 4 20 g. E,63.4 g. t-PBA.

(g; 1258 g. MA, 252 g. E, and 4 23 g. t-PBA.

300 g. EA, 336 g. E, and 21.2 g. t-PBA.

2512 g. EA, 300 g. E, and 28 g. methyl ethyl ketone peroxide. 0 g. EA,420 g. E, 35.1 g. d-t-BP, and 150 g.

hexane. I 344 g. MA, 560 g. E, 68.8 g. methyl proplonate, and

84 5 g. t PBA (9) 303 tgBIEA, 420 g. E, 150 g. hexane, and 40. 6 g.('10) 430 g. EA, 384 g. E, and 1300 g. chlorobenzene.

2 50 g. EA, 630 g. P, 1125 g. Skellysolve C, and 79. 1

g. d-t-BP. The resulting copolymer had a viscosity at 25 C. (G-H scale)of X, M.W.:772, P/EA ratio:1.'16, acid No.:0.t25, and color (Gardnerscale):'1. 215 g. MA, 630 g. P, 108 g. Skellysolve C, and 79.1

g. d-t-BP The resulting copolymer had a vis- (GH scale) of Z4, M.W.:684,

cosity at 25 C. P/EA I'HtiO lulE), acid No.:0.18 and color (Gardnerscale):1.

It was pointed out above that by keeping low the acid number of theethylene or propylene-acrylate or methacrylate plasticizers used in thepresent invention, e.g. 3.0 or below, the products plasticized therewithhave good volume resistivity. Such products also have advantages ofgreater compatibility and resistance to extraction by soapy water whencompared with materials having higher acid contents. The improvement involume resistivity is illustrated in Table III which follows:

TABLE III [Volume resistivity (ohms-cm. 10

Commercial DOP 4 Plasticizcr Compopolyesters 3 sition 90 C. dry 60 0.wet

0.10 About 0.1- 0. 42 do DOP is considered a good electrical gradeplasticizer, but it is too fugitive. Conventional polyesters, such aspolypropylene sebacates, are, on the other hand, poor in electricalproperties though they have good permanence. By comparison, as indicatedabove, the plasticized compositions of the present invention are veryuseful because they have better permanence and equivalent or superiorelectrical properties than similar polymers that are plasticized withDOP.

Another exceptional property of the novel ethylene or propylene-acrylateor methacrylate copolymer plasticized polyvinyl chloride compositions ofthe present invention is their excellent resistance to microorganisms.Normally, plasticized vinyl products are subject to attack by bactcriaand fungi, but such is not the case with the present products. Thisimprovement is illustrated in the following examples.

EXAMPLE An ethylene/ethyl acrylate (1:1) copolymer, made in accordancewith the method disclosed in US. Ser. No. 820,625, was employed as aplasticizer for a polyvinyl chloride homopolymer. This polymer had anapproximate molecular weight of 800 and a Gardner-Holdt viscosity of V+.It was prepared without any solvent. The plasticized product was placedin contact with a mineral salts agar nutrient medium having thefollowing composition:

Ammonium nitrate 'grams 3.0 Potassium dihydrogen phosphate do 1.0Magnesium sulfate do 0.5 Potassium chloride do 0.25 Agar do 15.0Distilled water mls 1000 The inoculum was selected from the followingmixture of fungi, and tests run with each mixture:

Pencillium funiculosum Penicillium piscarium Aspergillus flavusAspergillus niger Trichoderma viridc The incubation period was 21 days,the temperature was -95 F., and 85-90 R.H.

Samples were observed at the outset and the extent of growth observedafter 1 week, 2 weeks and 3 weeks. When an ethylene/ethyl acrylatecopolymer (ratio of 1.0) was used to plasticize a vinyl chloridehomopolymer the following results were observed:

The code used in determining the extent of growth of the mixed fungalinoculum on the vinyl chloridefilm was as follows:

=no growth 1=trace growth 2=slight growth, covering up to 25% ofspecimen 3=moderate growth, covering up to 25-75% of specimen 4=profusegrowth, covering 75-100% of specimen 5:profuse growth, covering all ofspecimen and heavily fruited As a control, by which to compare theforegoing result, the same test was run with a film of polyvinyl whichhad been plasticized with a fatty acid terminated polypropylene adipate.The results were as follows:

1 week 2 2 weeks 3 3 weeks 3 In summary, it is clear from the foregoingthat plasticized resinous compositions formed from homopolymers andcopolymers of vinyl chloride and, as the plasticizer, a liquid copolymerof ethylene or propylene and an acrylate made in accordance with themethod described in our parent US. application 820,625, are far superiorin many respects to prior art types of plasticized polymeric vinylchloride compositions.

We claim:

1. A plasticized resinous composition formed from a polymer of vinylchloride, selected from the group consisting of homopolymers of vinylchloride and copoly-mers of a major portion of vinyl chloride and anethylenically unsaturated monomer copolymerizable therewith, and, as aplasticizer, a liquid copolymer of an olefin from the class consistingof ethylene and propylene and an acrylate from the class consisting ofethyl acrylate, methyl acrylate, and methyl methacrylate, said copolymerhaving a viscosity in the range of from H to Z; for the ethylenebasedcopolymer and from H to Z for the propylenebased copolymer, both on theGardner-Holdt scale, an acid number which does not exceed 3, a molecularweight of between 500 and 1500, and a molar ratio of the olefin to theacrylic monomer from 1 to 3 when ethylene is the olefin and 0.5 to 2.0when propylene is the olefin, in which ratios the upper limit is afunction of molecular weight as expressed by the equations:

(A) Moles of ethylene/mole of acrylic monomer molecular weight WhereX=1.75 for ethyl acrylate and methyl methacrylate and X=2.25 for methylacrylate; and (B) Moles of propylene/mole of acrylic monomer X+(molecular weight where X=1.0 for ethyl acrylate and methyl methacrylateand X: 1.25 for methyl acrylate.

2. The composition of claim 1 in which the acrylic monomer is ethylacrylate and, when the olefin is ethylene, the value for X=1.'75.

3. The composition of claim 1 in which the acrylic monomer is methylmethacrylate and, when the olefin is ethylene, the value for X 1.75.

4. The composition of claim 1 in which the acrylic monomer is methylacrylate and, when the olefin is ethylene, the value for X:2.25.

5. The composition of claim 1 in which the acrylic monomer is ethylacrylate and, when the olefin is propylene, the value for X=1.0.

6. The composition of claim 1 in which the acrylic monomer is methylmethacrylate and, when the olefin is proplene, the value of X=1.0.

7. The composition of claim 1 in which the acrylic monomer is methylacrylate and, when the olefin is propylene, the value for X=1.25.

References Cited by the Examiner UNITED STATES PATENTS MORRIS LIEBMAN,Primary Examiner,

1. A PLASTICIZED RESINOUS COMPOSITON FORMED FROM A POLYMER OF VINYLCHLORIDE, SELECTED FROM THE GROUP CONSISTING OF HOMOPOLYMERS OF VINYLCHLORIDE AND COPOLYMERS OF A MAJOR PORTION OF VINYL CHLORIDE AND ANETHYLENICALLY UNSATURATED MONOMER COPOLYMERIZABLE THEREWITH, AND, AS APLASTICIZER, A LIQUID COPOLYMER OF AN OLEFIN FROM THE CLASS CONSISTINGOF ETHYLENE AND PROPYLENE AND AN ACRYLATE FROM THE CLASS CONSISTING OFETHYL ACRYLATE, METHYL ACRYLATE, AND METHYL METHACRYLATE, SAID COPOLYMERHAVING A VISCOSITY IN THE RANGE OF FROM H TO Z5 FOR THE ETHYLENEBASEDCOPOLYMER AND FROM H TO Z10 FOR THE PROPYLENEBASED COPOYLMER, BOTH ONTHE GARDNER-HOLDT SCALE, AN ACID NUMBER WHICH DOES NOT EXCEED 3, AMOLECULAR WEIGHT OF BETWEEN 500 AND 1500, AND A MOLAR RATIO OF THEOLEFIN TO THE ACRYLIC MONOMER FROM 1 TO 3 WHEN ETHYLENE IS THE OLEFINAND 0.5 TO 2.0 WHEN PROPYLENE IS THE OLEFIN, IN WHICH RATIOS THE UPPERLIMIT IS A FUNCTION OF MOLECULAR WEIGHT AS EXPRESSED BY THE EQUATIONS:(A) MOLES OF ETHYLENE/MOLE OF ACRYLIC MONOMER = X + 1/4(1500/MOLECULARWEIGHT) WHERE X=1.75 FOR ETHYL ACRYLATE AND METHYL METHACRYLATE AND X=2.25 FOR METHYL ACRYLATE; AND (B) MILES OF PROPYLENE/MOLE OF ACRYLICMONOMER = X + 1/4(1500/MOLECULAR WEIGHT) WHERE X=1.0 FOR ETHYL ACRYLATEAND METHYL METHACRYLATE AND X=1.25 FOR METHYL ACRYLATE.